Fix GCE VM image creation pipelines (part 1) (#2793) - Introduce new env variable to also re-create trusted instance groups in the final step. This is currently a no-op - we need to deploy this change via TF, then update https://github.com/bazelbuild/continuous-integration/blob/master/pipelines/publish-vm-image.yml. - Change image VM location - https://github.com/bazelbuild/continuous-integration/commit/8b0cc1baa274f7e575cdf1e2c3103879ad26027b wasn't enough, we're still running into quota issues in us-central1-c